New Industry Products

Laser Diode Driver ICs for Head-Up Displays and Pico Projectors

January 17, 2020 by Paul Shepard

Ricoh Electronic Devices Co., Ltd. in Japan has expanded its portfolio with two new Laser Diode Driver ICs targeted for laser scanning type automotive and consumer projector applications. The RN5C750 and RN5C752 are four-channel laser drivers that have been developed for use in RGB or RGGB laser scanning type screens and are equipped with many functions.

Laser driven projectors are now also becoming popular to use in specific automotive and consumer equipment, such as ADAS head-up displays for car dashboards and in portable Pico video projectors to view presentations and films. This change is a result of technology advances in electronics integration, ultra-small IC packaging and light sources.

Laser projectors have a significant advantage over conventional displays using LEDs, their color range is twice as large and its contrast ratio is much better for a crystal-clear visibility of the displayed content.

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The RN5C750 and RN5C752 offer a full HD resolution (1080p) and 60 fps image thanks to a fast laser diode output of 200 megapixel / sec and a high output current of up to 800mA (LD1) and 400mA (LD2-4). The laser diode outputs can tolerate voltages up to 10V to make it possible to use laser diodes with a high forward voltage.

In addition, power control for the laser diodes is performed by automatically adjusting the power source to save power and minimize heat dissipation. Contains various protection circuits such as laser diode overcurrent and short detection, thermal shutdown and photodiode overcurrent detection.

The RN5C750 has passed the AEC-Q100 (Grade 2) compatible reliability tests for automotive purposes and has a guaranteed operating temperature range from -40 to +105°C. The RN5C752 is an identical IC for consumer applications and has a temperature range from 0 to +70°C.

A special feature adopted from professional laser printers is used to deliver a high-quality output regardless of temperature. By using four additional photodiode sensors connected to the IC, it is possible to automatically detect the threshold current (Ith) and color current (Icolor) of each channel and maintains its color range regardless of temperature fluctuations.

The RN5C750 and RN5C752 are available in a QFN0808-56 package with a wettable flank technology that improves the solderability of the chip and enables better automatic visual inspection of the solder joint after mounting on the printed circuit board. 7-bits dimming is possible by a simple setting in a specific register; there is no need to adjust the video data stream.

Samples and evaluation boards are available through Ricoh's global local distribution network.

Summary of Features RN5C750, RN5C752

  • RGGB 4-Channel Current Output (Sink)
  • LD1 (R) Maximum Operating Current: Iop = 800mA (Icolor = up to 500mA, Ith = up to 300mA)
  • LD2 to 4 (GGB) Maximum Operating Current: Iop = 400mA (Icolor = up to 250mA, Ith = up to 150mA)
  • Maximum Output Rate per 1 Channel: 200 Megapixel / sec
  • High Gradation Output by Using 10-Bit Color DAC
  • High Speed Output of Typically 1.0-ns Rising/Falling
  • 20-bit Parallel Input Video I/F, Maximum Clock Frequency: 200MHz, LVCMOS I/F
  • 10-bit Parallel Input Video I/F, Maximum Clock Frequency: 225MHz, LVCMOS I/F
  • 10V LD Pin Corresponding to High Forward Voltage (Vf) LD
  • Power Saving and Heat Generation Suppression of Package by Using LD Power Source Control
  • Protections: LD Overcurrent, LD Pin Short Circuit, PDI Input, Thermal Shutdown
  • Pulse-Off Function, Dimming Function
  • 12-bit SAR-ADC
  • Serial Port Control by Using SPI Communication, SPI Maximum: 25 MHz
  • Operating Temperature Range RN5C750 / RN5C752: −40 to 105°C / 0 to 70°